Here is the data for the Soviet Union for the 20th century. (Second link in contents will take you to a graph and a spreadsheet) You can see the effects of the Russian revolution and subsequent NKVD purges. And you can see the effect of WWII. However, the figures for recovery might not be exactly fair as the USSR expanded its borders during WWII.

So here (third link in contents will take you to spreadsheets the first two columns of which show year and respective total population) is similar data for Russia alone. Again, the impact of WWII is pretty noticeable and as you can see the population recovers in number sometime in the mid 50s.

However, due to the sheer volume of wars and other shit that Russia went through during the 20th century, the population is still plagued by a gender imbalance, so in that sense, you could say it's still recovering.